The closest airports are Brussels, Charleroi (Brussels South Charleroi Airport) and Liège.
From Brussels, the train to Dinant takes 1 hr 30 minutes.
The train station is conveniently located in the centre of Dinant, about 5 minutes walk to the river (from where you can see the Citadel and the main parts of Dinant)
From Brussels, take the A4 south for 80 kilometers and follow the signs into town.
No need to take public transport at all since Dinant is a very small town and the main tourist sites are within walking distance.
On a cliff, more than 100 meters above the River Meuse, the Citadel of Dinant offers spectacular views of the town and countryside. A fortification may have stood on this spot as long ago as the fourth century, and the Bishop Prince of Liège certainly ordered the construction of a fortress on this spot in 1051, but the present structure dates to the early 19th century. It is reached from the town either by cable car or by the 408 steps cut into the hillside. The citadel plays host to a small Arms Museum and several interesting objets d'art that reveal the glorious past of this Meuse town.
A visit to the beautiful La Merveilleuse caves (Grotte la Merveilleuse) is highly recommended. A 50-minute guided tour costs 8€ for adults and 5€ for children (2010 prices).
Along the river, next to the departure points of boat tours, there is a Match supermarket. Buy some groceries and enjoy a picnic by the riverside!